Food production is now so energy-intensive that more carbon is emitted providing a person with enough calories to walk to the shops than a car would emit over the same distance. The climate could benefit if people avoided exercise, ate less and became couch potatoes.
So you mean to tell me that it takes (gasp) energy to keep a person running?!? Say it isn't so!!!
Ah, don't worry about it. Come to my place, and we'll sit on my porch, and watch the sunset over an ice-cold glass of carbon-free raspberry lemonade. Mmmmm, taste that raspberry sweetness.